128层螺旋CT低管电压技术在头部减影CTA中降低辐射剂量的临床应用研究

发布时间：2018-05-14 11:12

本文选题：计算机体层摄影 + 低管电压　；参考：《泸州医学院》2013年硕士论文

【摘要】：目的：通过对比分析低管电压（80kV、100kV）与常规管电压（120kV）扫描在头部减影CT血管成像（DS-CTA）中对辐射剂量及图像质量的影响，评价低管电压、低辐射剂量扫描在头部DS-CTA中的临床应用可行性及价值。方法：将2012年10月-2013年3月期间在我院就诊临床需要做头部DS-CTA的所有成年人患者纳入本次研究，共57例（男31例,女26例,年龄37-85岁,平均年龄62.4岁），按随机分配原则分别编入不同管电压组，即A（80kV）、B（100kV）、C（120kV）三组，，其中A组共19例、B组共20例、C组共18例，在其他扫描参数基本一致的情况下，记录三组不同管电压扫描条件下所产生的辐射剂量（CT剂量指数（CTDIvol）、剂量长度乘积（DLP）、有效剂量（ED）），并从主观、客观两方面评价三组图像质量的差异，其中客观评价包括头部各段血管平均强化CT值（SI）、噪声、信噪比(SNR)及对比噪声比（CNR）,主观评价则由2名有经验的影像科医师采用5分评价法分别对原始图像、二维、三维图像质量进行盲法独立评价。采用单因素方差分析比较三组间辐射剂量及血管CT值、图像噪声、CNR、SNR的差异；采用非参数秩和检验比较三组图像间的主观评分差异；采用Kappa检验评价2名观察者间的一致性。统计学结果P0.05认为差异有统计学意义,K0.60认为一致性较好。结果：1.辐射剂量结果：低管电压A、B组（80kV、100kV）的辐射剂量指标（CTDIvol、DLP、ED）较常规常规管电压C组（120kV）均明显降低，其中尤以80kV组辐射剂量指标降低显著，三组间差异具有统计学意义。2、图像质量的客观评价结果：随着管电压逐步降低，血管强化CT值及图像噪声值均逐渐增高，三组间差异具有统计学意义，但三组间血管的CNR、SNR值差异无统计学意义。3、图像质量的主观评价结果：随着管电压降低,血管边缘的锐利程度降低，细小血管分支显示增多，静脉干扰加大，但三组间的MIP、MPR、VR图像质量的评分及图像整体质量的评分差异均无统计学意义,且图像质量差异不会影响到脑血管疾病的诊断。4、两位观察者评分的一致性较好。结论：128层螺旋CT低管电压扫描技术在头部DS-CTA中可以明显降低其辐射剂量、增加血管强化CT值，而对图像质量及临床诊断没有明显影响，具有临床应用可行性。
[Abstract]:Objective: to evaluate the effects of low-tube voltage (80kV) and conventional tube voltage (120kV) on radiation dose and image quality in head subtraction CT angiography (DS-CTAA). Feasibility and value of low radiation dose scanning in head DS-CTA. Methods: from October 2012 to March 2013, 57 adult patients (31 males, 26 females, aged 37-85 years) with head DS-CTA were enrolled in this study. The average age was 62.4 years old. According to the principle of random distribution, they were divided into three groups, namely, AH80kV BX 100kVV (120kV) group. There were 19 cases in group A, 20 cases in group B, 20 cases in group C, 18 cases in group C, and 18 cases in group A, and 18 cases in group C, with the same scanning parameters. Three groups of radiation doses produced under different tube voltage scanning conditions were recorded. The CT dose index (CTDIvoll), the dose length product (DLPX) and the effective dose (EDV) were recorded. The difference of image quality between the three groups was evaluated from subjective and objective aspects. Objective evaluation included the mean enhancement CT value of each segment of the head, noise, SNR) and contrast noise ratio CNR.The subjective evaluation was used by two experienced imaging physicians to evaluate the original image, 2-D, 2-D, respectively. Three-dimensional image quality was evaluated by blind method. Single factor analysis of variance (ANOVA) was used to compare the difference of radiative dose and vascular CT value, image noise and SNR, nonparametric rank sum test was used to compare the subjective score differences among the three groups, and Kappa test was used to evaluate the consistency between two observers. Statistical results P0.05 that the difference was statistically significant (K 0.60) that the consistency was better. The result is 1: 1. The results of radiation dose showed that the radiation dose index (CTD) of low tube voltage ANAB group (80 kV / 100kV) was significantly lower than that of conventional tube voltage group C (120kV), especially the radiation dose index of 80kV group was significantly lower than that of conventional tube voltage group C (P < 0.05), and the radiation dose index was significantly lower than that of conventional tube voltage group C (P < 0.05), especially in the 80kV group. The difference among the three groups was statistically significant. The objective evaluation results of image quality showed that the CT value and image noise value of vascular enhancement increased gradually with the decrease of tube voltage, and the difference among the three groups was statistically significant. However, there was no significant difference in CNRN SNR between the three groups. The subjective evaluation results of image quality were as follows: with the decrease of tube voltage, the sharp degree of vessel edge was decreased, the number of small vessel branches was increased, and the venous interference was increased. However, there was no significant difference in the image quality and the overall image quality between the three groups, and the difference in image quality did not affect the diagnosis of cerebrovascular diseases. Conclusion the low tube voltage scan technique of 128-slice spiral CT can significantly reduce the radiation dose and increase the CT value of vascular enhancement in head DS-CTA, but it has no obvious influence on image quality and clinical diagnosis, so it is feasible in clinical application.
【学位授予单位】：泸州医学院
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R816.1

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